Virtually the same proportion diabetic heart patients -- 88 percent -- were alive after five years whether doctors used a surgical or non-surgical approach to treatment, researchers reported at the American Diabetes Association.

Likewise, there was no statistical difference in how likely patients were to remain free of heart attack, stroke and other major heart problems.

Dr. Trevor Orchard of the University of Pittsburgh, lead author of the study, said the results mean that most diabetic heart patents can stay on non-surgical therapy unless their arteries become so blocked that there's no other option.

"There's no compelling reason for urgency," he said.

For cardiologists, the research project, known as Bypass Angioplasty Revascularization Investigation 2 Diabetes study (BARI 2D), provided more conclusive proof that there is relatively little advantage in bypass surgery or stenting in most cases, even with patients whose heart disease is complicated by diabetes.

It's the latest round in an old debate about whether to treat patients who have narrowed coronary arteries with medicine or to use surgical procedures.

The surgical procedures go by the general term "revascularization" because they deal with the blood vessels that supply the heart.

A doctor threads a balloon-shaped tube from an artery in the groin to a blocked artery in the heart. The balloon is inflated, compressing the plaque blocking the artery and widening it to allow increased blood flow. The doctor may also insert a wire mesh tube called a stent, which props the artery open for a longer-lasting fix.

The advantage of PCI is that it doesn't require opening the body, although it is still a surgical procedure and considered riskier than treating heart disease with medicine alone.

Surgery Can't Beat Heart Drugs for Diabetic Patients, Study Suggests

In bypass surgery, surgeons take arteries or veins from another part of the body and graft them onto the heart, providing unobstructed new pathways that bypass clogged arteries. This is open heart surgery, which is commonplace today but still potentially far riskier than non-surgical treatment.

The BARI 2D findings -- that patients are no more or less likely to die no matter which approach doctors take -- match evidence from an earlier trial known by the acronym COURAGE, according to an editorial that accompanied the online publication of BARI 2D in the New England Journal of Medicine.

Given the popularity of stents and bypass surgery -- and the assumption that they were superior to non-surgical treatment -- that trial created shock waves in the cardiology world.

But COURAGE also suggested that bypass surgery might still be more beneficial for heart patients who also had diabetes.

In fact, most doctors believed that diabetes patients who also had coronary artery disease would fare best with the most aggressive treatment, said Dr. Randal J. Thomas, a Mayo Clinic cardiologist who was not involved in the study.

To test that hypothesis, Orchard's group assembled an international group of 2,368 patients with both Type-2 (adult-onset) diabetes and stable ischemic heart disease.

Participants were randomly assigned to conventional medical therapy, including the most popular drugs to control diabetes, or to a surgical procedure -- stenting or bypass surgery at the physician's discretion.

With drugs, the researchers maintained all patients at the same blood sugar level.

Although the study showed no overall advantage for either kind of treatment, bypass surgery did show a slight advantage over stents and non-surgical treatment in preventing the occurrence of future serious coronary events -- but not death.

This finding was striking, said co-author Dr. Robert Frye, also a Mayo Clinic cardiologist.

"It's the first demonstration in a properly conducted randomized trial that -- in patients with mild symptoms and stable ischemic heart disease -- coronary bypass reduces these events," he said at a news conference Sunday regarding the findings.

Medical Community Stops Shy of Full Endorsement of Drugs Over Surgery

In its editorial, the New England Journal of Medicine stopped short of a flat-out endorsement of drug treatment over surgical intervention.

Instead, it called non-surgical therapy "an excellent first-strategy, particularly for those with less severe disease." But for those with more serious coronary artery blockage and symptoms, it said, "revascularization is appropriate," using either strategy.

Critics of the study noted that the results might not be applicable to a population with unstable heart disease and other populations.

Still, the study suggests there are many patients who could safely start with the less expensive, less intensive and more prevention-oriented therapies, according to the Mayo Clinic's Thomas.

These patients may represent "low hanging fruit" for reducing health care expenses while still administering appropriate therapy, he said.

The annual cost of health care for an adult with diabetes is about $10,000, compared with around $3,000 for a non-diabetic adult.

The study was supported by grants from the National Heart, Lung and Blood Institute and the National Institute of Diabetes and Digestive and Kidney Diseases; and by GlaxoSmithKline, Lantheus Medical Imaging, Astellas Pharma, Merck, Abbott Laboratories, Pfizer, MediSense, Bayer, Becton Dickinson, J.R. Carlson Labs, Centocor, Eli Lilly, LipoScience, Novartis, and Novo Nordisk.

Orchard reported receiving consulting fees from AstraZeneca, Eli Lilly, and Takeda and grant support from VeraLight and having an equity interest in Bristol-Myers Squibb.